6 



than one line in diameter, the more common width being about two-thirds 

 of a line, their margins thin, distinctly elevated above the general surface, 

 and, in perfect specimens, crenulated or serrated with twelve small, rough, 

 pointed tubercles. Septa rudimentary, rarely visible; but in certain condi- 

 tions of preservation distinctly striating the inside of the cells and tubes 

 below. The tabulae are usually horizontal, three or four in one line. Owing 

 to the close arrangement of the tubes there is very httle coenenchyma, and 

 this is vesicular. 



When the cells are closely crowded together they become more or less 

 prismatic with polygonal apertures, and it is then difficult to distinguish 

 the specimens from certain species oiFavosites. In general, hoVever, they 

 are circular although in contact or nearly so. Colonies are occasionally 

 found with the cells distant about half their diameter. 



The species to which this is most nearly related is H. tuhulata (Lons- 

 dale), common in the Wenlock limestone. That species, however, as 

 described by McCoy, Edwards and Haime and others, has the cells in 

 general somewhat smaller and the apertures not so strongly serrated. 



The crenulations on the margins of the cells are only visible when the 

 surface is not at all abraded. The least wearing removes them, and the 

 apertures are then simply circular or sub-polygonal. 



This species has been found at Wreck Point ; H. R. Also at White 

 CUff, Junction Cliif, Wall's Cove, South Point and other localities, in 

 Divisions 1, 2 and 3, A. G. J. Richardson and T. C. Weston. 



Genus Favosites, Lamarck. 



F. PROLiFicus, B., op. cit., p. 429. — Corallum forming large hemispheric 

 or irregularly convex masses. Tubes about one line in diameter. Tabulae 

 thin and either complete or imperfect, sometimes filling the tube with vesi- 

 cular tissue. They are often very numerous, there being sometimes six or 

 seven in one line. No septa or mural pores have yet been detected, and it 

 may be that this species should be placed in another genus. Hudson River 

 formation and throughout the Middle Silurian. J. Richardson and T. C. 

 Weston. — (-F. prolificus, Billings, — loc. cit. F. Gothlandica, pars, Geol. 

 Can. p. 221, 222, 299, 301, 302, 303, 304, 306, 307.) 



F. CAP AX, n. sp. — Corallum forming large depressed hemispheric or 

 irregular masses. Tubes, when full grown, about two lines in diameter ; a 

 few of smaller size scattered among the larger. Tabulae thin, flat, hori- 

 zontal, sometimes convex or concave and oblique ; about one line distant. 

 Inner faces of the tubes obscurely striated longitudinally and wrinkled 

 transversely. Pores small, situated in the angles of the tubes but none 

 were observed on the faces. This species, in the position of the pores, 

 resembles F. alveolaris, Goldfuss, and also, F. aspera, D'Orbigny (Ed- 



